La Niña continued over the past month, as indicated by the strengthening of below-average sea surface temperatures (SSTs) across the central and eastern equatorial Pacific Ocean [Fig. 1]. The latest weekly Niño indices were between -0.5°C and -0.7°C, with the exception of the easternmost Niño-1+2 index at -0.2°C [Fig. 2]. Negative subsurface temperature anomalies persisted (averaged from 180°-100°W; [Fig. 3]), with below-average temperatures prevailing from the surface to 200m depth in the eastern half of the equatorial Pacific [Fig. 4]. The atmosphere continued to reflect La Niña, with low-level easterly wind anomalies and upper-level westerly wind anomalies observed across most of the equatorial Pacific Ocean. Enhanced convection persisted over Indonesia and was weakly suppressed near the Date Line [Fig. 5]. Both the traditional and equatorial Southern Oscillation indices were positive. Collectively, the coupled ocean-atmosphere system reflected La Niña.

The IRI multi-model predictions favor La Niña to continue through December-February (DJF) 2025-26 [Fig. 6]. While also considering predictions from the North American Multi-Model Ensemble, the ENSO team believes uncertainty for the DJF season is high with La Niña (51% chance) slightly favored over ENSO-neutral (48% chance). La Niña is expected to remain weak (3-month average Niño-3.4 index value at or between -0.5°C and -0.9°C). A weak La Niña would be less likely to result in conventional winter impacts, though predictable signals could still influence the forecast guidance (e.g., CPC's seasonal outlooks). In summary, La Niña is favored to continue into the Northern Hemisphere winter, with a transition to ENSO-neutral most likely in January-March 2026 (61% chance; [Fig. 7]).